Simple Object Access Protocol (SOAP) is a standard way for web services to talk with one another. SOAP is a protocol for exchanging structured data payloads between systems. The SOAP specification defines a common way to send requests to web services to initiate functionality and receive responses. Both requests and responses can pass parameters that inform the process in place. SOAP is based on XML, the markup language, and exchanges these XML documents over HTTP. SOAP is still in wide use, yet viewed as outmoded by many developers that use more modern API formats, such as RESTful APIs that send JSON over HTTP.